title: Computation and experiment reveal that the ring-rearrangement metathesis of Himbert cycloadducts can be subject to kinetic or thermodynamic control.
abstract: Unusual observations in the ring-rearrangement metathesis of Himbert arene/allene cycloadducts to form fused polycylic lactams led to a more in-depth experimental study that yielded conflicting results. Differences in reactivity within related systems and unexpected changes in diastereoselectivity among other similar substrates were not readily explained on the basis of the experimental results. Computational investigations demonstrated substrate-dependent changes in reaction pathways (ring-opening metathesis/ring-closing metathesis [ROM/RCM] cascade vs ring-closing metathesis/ring-opening metathesis [RCM/ROM] cascade). Furthermore, some reactions were judged to be under thermodynamic control and others under kinetic control. The greater understanding of the most likely reaction pathways and their energetics provides a reasonable explanation for the previously irreconcilable results.
authors.affiliation: 1102 Natural Sciences II, Department of Chemistry, University of California , Irvine, California 92697-2025, United States.
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Lam
authors.forename: Hung V
authors.initials: HV
authors.lastname: Pham
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Vanderwal
mesh_terms: D003500:Cyclization; D007700:Kinetics; D015394:Molecular Structure; D011789:Quantum Theory; D013237:Stereoisomerism; D013816:Thermodynamics